Imaging apparatus having rotary table

Abstract: In an imaging apparatus with rotary table having a plurality of control items, operation completion of control items, such as horizontal angle, vertical angle, zoom and focus, of the imaging apparatus and the rotary table is detected by respective completion detectors (17, 27) and so on. On the basis of the logical product of all operation completion signals, an AND circuit 3 permits control toward the next desired value.

Description: The present invention relates to an imaging apparatus having a rotary table to be used for monitoring and recording. Fig. 4 is a block diagram showing the configuration of a conventional imaging apparatus. With reference to Fig. 4, n combinations of desired position data with respect to control items of four kinds 1(n) to 4(n) are stored in a preset unit 2. One arbitrary combination is selected according to an input supplied from a controller 41. A comparator 13 is supplied with selected desired position data of 1(n), such as 1(2). Its output is inputted to a horizontal-angle control motor 15 via a driving amplifier 14. Turning force of the motor 15 drives horizontal rotation of a rotary table via a reduction gear or the like. The horizontal angle of the rotary table is detected by a position sensor 16 and inputted to the comparator 13. A comparator 23 is supplied with desired position data, such as 2(2), of the preset unit 2. A vertical-angle control motor 25 drives vertical rotation of the rotary table. In addition, a series of operations of a driving amplifier 24, the motor 25, and a position sensor 26 are the same as those of the driving amplifier 14, the motor 15, and the position sensor 16. In completely the same way, numerals 33 and 43 denote comparators. The comparators 33 and 43 are supplied with desired position data 3(2) and 4(2), respectively. Numerals 34 and 44 denote driving amplifiers, and numerals 35 and 45 denote zoom-control motor and focus-control motor. The driving amplifier 34 and the motor 35 drive the zoom, whereas the driving amplifier 35 and the motor 45 drive the focus. Numerals 36 and 46 denote position sensors. Operation of the conventional imaging apparatus having the above described configuration will now be described. Among one set of data selected by a movement instruction, desired position data of horizontal angle 1(2), desired position data of vertical angle 2(2), desired position data of zoom 3(2), and desired position data of focus 4(2) are inputted to the comparators 13, 23, 33 and 43, respectively. In the comparator 13, the desired position data 1(2) supplied from the preset unit 2 is compared with the output of the position sensor 16. An output proportionate to the difference between them is amplified by the driving amplifier 14. The amplied output is supplied to the motor 15. The angle of the rotary table rotated horizontally by the rotation output of the motor 15 is converted into an electric signal by the position sensor 16. The electric signal is fed back to the comparator 13. If the horizontal angle has reached the desired position data value, the motor 15 is stopped. Operations of control items of three other kinds are also conducted in the same way. In this way, the conventional imaging apparatus can move to respective desired values of various control items set beforehand and take a desired image according to a command given from the controller. In the above described conventional imaging apparatus, time lengths required for movement from initial positions respectively of the horizontal angle and vertical angle of the rotary table to next desired positions are not equal, in general, between the horizontal rotation and vertical rotation. In case the vertical rotation, for example, is completed earlier the imaging apparatus goes straight ahead obliquely in the direction of composition of the horizontal speed and the vertical speed during the vertical rotation whereas the imaging apparatus goes straight ahead in the horizontal direction after the vertical rotation has been completed. Therefore, the movement direction of the screen is bent. This results in the problem that the observer feels a malaise. WO 91/02287 describes a surveillance camera system which discloses the features defined in the preamble of claim 1. It would therefore be desirable to provide an excellent imaging apparatus with rotary table requiring the same time for both horizontal rotation and vertical rotation and hence moving on a straight line extending from an initial position to a desired position. Thus, in accordance with the present invention there is provided an imaging apparatus with a rotary table as defined in claim 1. Since movements of horizontal angle and vertical angle are thereby completed at the same time, the imaging apparatus moves on a straight line. Thus, image movement does not provide feeling of a malaise. Is thus possible to realize an excellent imaging apparatus with rotary table in which the horizontal angle and vertical angle simultaneously arrive at desired control positions. Fig. 1 is a block diagram showing the configuration of an arrangement which does not constitute an embodiment of the present invention; Fig. 2 is a block diagram showing the configuration in an embodiment of the present invention; Fig. 3 is a diagram illustrating the operation of the embodiment of the present invention; and Fig. 4 is a block diagram showing the configuration according to the prior art. Fig. 1 is a block diagram showing the schematic configuration of an arrangement which does not constitute an embodiment of the present invention. In Fig. 1, components having the same numerals as those of Fig. 4 have like names and functions and will not be further described. Numeral 1 denotes a controller, whose output is inputted to a preset unit 2. Numeral 3 denotes an AND circuit, whose output is inputted to the controller 1. Numerals 17, 27, 37 and 47 denote completion detectors supplied with outputs of comparators 13, 23, 33 and 43, respectively. All outputs of the completion detectors 17, 27, 37 and 47 are inputted to the AND circuit 3. Operation of the imaging apparatus configured as heretofore described will now be described by referring to Fig. 1. First of all, the controller 1 issues a movement instruction. Thereby, one specified set, such as (2) for example, is selected out of n sets of desired position data preset in the preset unit 2. Desired position data 1(2), 2(2), 3(2) and 4(2) are thus inputted to the comparators 13, 23, 33 and 43. Data 1(2), 2(2), 3(2) and 4(2) are desired position data of horizontal angle, vertical angle, zoom and focus, respectively. In the comparator 13, the desired position data 1(2) supplied from the preset unit 2 is compared with the output of the position sensor 16. The output of the comparator 13 proportionate to the difference between them is amplified by the driving amplifier 14. The difference thus amplified is supplied to the horizontal-angle control motor 15. The horizontal angle of the rotary table rotated horizontally by the rotation output of the motor 15 is converted to an electric signal by the position sensor 16. The electric signal is fed back to the comparator 13. If the horizontal angle reaches the desired value, the motor 15 is stopped. At this time, the output of the comparator 13 has a value of 0. Therefore, the completion detector 17 detects this and inputs the detected output to the AND circuit 3. Operations of control items of three other kinds are conducted in the same way. Only when all of detection outputs from the comparators 13, 23, 33 and 43 are supplied to the AND circuit 3, it sends its output to the controller 1. Recognizing that movements for all control items have been completed, the controller 1 may indicate that fact by using a pilot lamp. Or after a required imaging time has elapsed, the controller may automatically proceed to the next movement instruction. Fig. 2 is a block diagram showing the schematic configuration of an embodiment of the present invention. Fig. 3 is a diagram illustrating the operation of this embodiment. In Fig. 2, components having the same numerals as those of Fig. 1 have like names and functions and will not be further described. Numeral 5 denotes a computing circuit. The computing circuit 5 is supplied with outputs of the positions sensors 16 and 26 and output of the preset unit 2. The output of the computing circuit 5 is supplied to the driving amplifiers 14 and 24. Operation of the embodiment configured as described above will now be described as to difference from the operation of the arrangement described with reference to Figure 1. On the basis of a desired position data group selected in the preset unit 2 by the controller 1, such as 1(2) and 2(2), and current position information pieces outputted by the position sensors 16 and 26, the computing circuit 5 calculates time values required for movement respectively in horizontal angle and vertical angle. Fig. 3 is a graph showing the horizontal angle and vertical angle. With reference to Fig. 3, it is now assumed that current horizontal and vertical positions are respectively P3 and T3 whereas desired horizontal and vertical positions are respectively P4 and T4. Assuming that horizontal movement speed and vertical movement speed are V P and V T , respectively, horizontal and vertical movement time are given by the following equations. Horizontal movement time = (P4 - P3) / V P Vertical movement time = (T4 - T3) / V T During an interval from the point of coordinates (P3, T3) until the vertical movement is completed, the conventional rotary table moves in a direction of a composite vector of the horizontal movement speed and vertical movement speed as indicated by a broken line in Fig. 3. After the vertical movement has been completed upon reaching T4, the conventional rotary table moves in the horizontal direction until P4 is reached. Thus the conventional rotary table traces a bent path. In the embodiment, the computing circuit 5 compares time values required for movements. If, for example, the time required for movement of vertical angle is shorter, a signal for controlling the driving amplifier 24 so as to make the vertical speed equal to the value of the following equation is outputted in order to make the vertical movement time equal to the horizontal movement time. Vertical speed = V P × (T4 - T3) / (P4 - P3) If the time required for movement of horizontal angle is shorter, a signal for controlling the driving amplifier 14 so as to make the horizontal speed equal to the value of the following equation is outputted. Horizontal speed = V T × (P4 - P3) / (T4 - T3) Since the time required for horizontal movement thus becomes equal to the time required for vertical movement, the rotary table which has started from the point (P3, T3) can move on a straight line toward the point (P4, T4). Therefore, there is no bents in the movement path, the image observer feels no malaise. In the embodiment, the motors 15, 25 and so on have been shown as power sources. Alternatively, actuators using oil pressure, gas pressure or the like may also be used. Furthermore, horizontal angle, vertical angle, zoom and focus have been mentioned as examples of control items. However, iris of the lens and the like may be included in the control items.

Claims: An imaging apparatus with a rotary table, said rotary table comprising: control means (1,2) for selecting one set out of a plurality of sets of desired position data preset for control and for causing operation, with respect to control items of a horizontal angle and a vertical angle of said rotary table; power sources (15, 25, 35, 45) provided for respective control items to cause movement toward desired positions; driving means (14, 24, 34, 44) provided for respective control items to drive power sources; and position sensors (16, 26, 36,46) provided for respective control items to generate current position information; characterised in that said imaging apparatus further comprises: computing means (5) for calculating time values respectively required for horizontal movement and vertical movement on the bases of: (a) a predetermined horizontal speed and a predetermined vertical speed and (b) desired position data of respective control items and outputs of position sensors of respective control items, and for deriving such control outputs as to cause either the horizontal speed or the vertical speed to be less than its associated predetermined value, thereby to make the shorter one of the required time values equal to the longer time value, thereby to cause the horizontal angle and the vertical angle simultaneously to arrive at the desired positions for control.

Inventors: WADA JYOJI, WADA, JYOJI
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1994
Main classification: H04N5
IPC codes: H04N7, H04N5